I also have an 08 Malibu VLX great boat! You will not be able to film quality footage with a GoPro at a rider 70 feet back. We use the GoPro when riding doubles or filming from a tube. I suggest getting an older model Canon HD camcorder such as an HG10 and looking into WakeJak's camera mount for the tower. When we film from the boat we usually have whoever isn't riding or one of the girls film from a tripod in the back.